1. Field of the Invention
This invention generally relates to bicycle hydraulic brake device. More specifically, the present invention relates to bicycle hydraulic brake (actuation) device that includes an adjustment mechanism for adjusting a free stroke of an operating member and for adjusting a rest position of the operating member.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. Specifically, bicycle braking systems have been extensively redesigned.
In recent years, bicycles have been provided with hydraulic braking systems. A hydraulic brake system typically includes a hydraulic brake actuation device, a rotor attached to one of the bicycle wheels and a brake caliper having a slot that receives the rotor therein. The caliper has brake pads that selectively contact the rotor in response to changes in hydraulic pressure in the hydraulic brake actuation device when an actuator such as a lever is moved. Bicycle typically include a front braking system to apply a braking force to the front wheel and a rear braking system to apply a braking force to the rear wheel.
A hydraulic brake actuation device typically has a housing mounted to the bicycle handlebar. The housing includes a master cylinder, a master piston disposed in the master cylinder and a brake lever pivotally supported on the housing. Pivoting movement of the brake lever provides leverage for moving the master piston in the master cylinder, which in turn causes movement of one or more slave pistons in the caliper. Typically, the brake pads are spaced apart from braking surfaces of the rotor until moved into braking contact with the rotor by movement of the slave piston(s).
Typically, when the brake lever of the hydraulic brake actuation device is moved, the slave cylinder(s) also move a corresponding amount. Such an arrangement can result in a strong braking force relatively early in the range of movement of the brake lever. Such a braking action can feel unnatural as compared to using cable actuated rim brakes. Moreover, with this arrangement, a higher than desired braking force may be applied (i.e., the brake action may slow the rider more quickly than desired). Accordingly, some hydraulic braking systems have been provided which have a free stroke. A free stroke is a range of movement of the brake lever during which the slave cylinder(s) do not move. While these braking systems utilizing a free stroke generally work well, the amount of free stroke is not always optimum for all riders or riding conditions. Additionally, typical hydraulic brake actuation devices utilize a set rest or start position for the brake lever. Unfortunately, the set rest or start position of typical hydraulic brake actuation devices is not always optimum for all riders or riding conditions.
Accordingly, more recently, some hydraulic brake systems have been provided that have an adjustable free stroke and/or rest position. While these adjustable systems generally work well, these adjustable systems have disadvantages. Specifically, the typical adjustable systems can be relatively complicated (e.g., utilize numerous parts) and/or expensive to manufacture and/or assemble. Moreover, with these adjustable systems, it can be relatively cumbersome to adjust the free stroke and/or the rest position. Furthermore, with these typical adjustable hydraulic brake systems, it can be difficult and/or even impossible to adjust the free stroke or rest position without also adjusting the other.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved hydraulic brake (actuation) device. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.